The objective of this proposal is to create the genomic resources and infrastructure for the colonial protochordate, Botryilus schlosseri. B. schlossei is a laboratory reared, genetically manipulable organism with a life history that includes a number of unique and experimentally accessible developmental and immunological processes, making it a potential model organism for a variety of studies. These include a histocompatibility system analogous to that controlled by the MHC in vertebrates, stem cells with the ability to parasitize related individuals in a genetically determined hierarchy, and two separate developmental programs- one sexual and the other asexual-that result in morphologically and functionally identical body plans. The protochordates represent the ancestral vertebrates, and this close phylogenetic relationship suggests that the genes and regulatory mechanisms that control these biological phenomena in Botryllus are Iconserved and relevant to vertebrate biology. This proposal will create: a complete genetic and initial physical map of the B. schlosseri genome; a number of normalized and arrayed cDNA libraries; an EST database of 4-5,000 clones from these normalized libraries, and the development of transgenic and/or transient gene expression systems. In addition, these resources will be used to generate preliminary data for future funding. [unreadable] [unreadable]